Lightning or power lines ?

[Horse Newbie 7,057]

Okay all you engineers, physicists, and scientists, take a look at these pics I took at work today and tell me what caused this damage to a concrete sidewalk...

Edited March 6, 2021 by Horse Newbie

[bc.gold 3,403]

Kids prbably got their hands on a couple of sacks of thermite, used by the railways for track welds.

 

Thermite burns at about 5000 degrees F., or half the temperature at the surface of the sun.

How deeply it will burn of course depends on the amount of fuel available. Most of the heat, of course, will go upward. Some ash will form, which will insulate the concrete to a degree, and further impede downward burning. So, as a guess, I would think it would only burrow down an inch or two before the fuel burns out, even for a big charge.

 

 

 

 

Edited March 6, 2021 by bcgold

[Jeff-C175 7,199]

40 minutes ago, Horse Newbie said:

what caused this damage

 

Is there a back story?  Do you know the answer?

 

I'm not going to guess...

[8ntruck 6,991]

Extra spicy Jack in the Box burger maybe?

[ebinmaine 67,309]

This is proof that littering does FAR more short term damage than we thought. 

[ebinmaine 67,309]

I gotta go 🌩️🌩️⚡⚡⚡⚡ Lightning ⚡⚡⚡⚡⚡⚡

[ranger 1,746]

A classic case of “S.S.C. ( Spontaneous Sidewalk Combustion). 💥. Or perhaps the latest “Tesla” electric bicycle 🚲 “Peeling out?” 🚴‍♂️

Edited March 6, 2021 by ranger

[ebinmaine 67,309]

14 minutes ago, ranger said:

A classic case of “S.S.C. ( Spontaneous Sidewalk Combustion).

Well done ranger. I'd forgotten all about that. 

[Mickwhitt 4,593]

Buried power cable failure.

 

We had one near where I worked as a cop, report of fire coming up through the pavement. 

 

Pretty spectacular in a country where our last active volcano was witnessed by didlosaurs. Lol

[squonk 41,038]

Buried primary lines can do a lot of damage when they take a dump! 

[ranger 1,746]

1 hour ago, squonk said:

Buried primary lines can do a lot of damage when they take a dump! 

Especially when a digger/backhoe takes a “bite” out of one! ⚡️🚒🚑🏥⛪️⚰️🕳 or if you’re very lucky, you may only need this 🚽🧻🧻

[oldlineman 1,481]

I would go with Mick, have seen similar with URD failure and also with energized over head lines down and protection equipment not clearing line for various reasons. Bob 

[ranger 1,746]

9 hours ago, bcgold said:

Kids prbably got their hands on a couple of sacks of thermite, used by the railways for track welds.

 

Thermite burns at about 5000 degrees F., or half the temperature at the surface of the sun.

How deeply it will burn of course depends on the amount of fuel available. Most of the heat, of course, will go upward. Some ash will form, which will insulate the concrete to a degree, and further impede downward burning. So, as a guess, I would think it would only burrow down an inch or two before the fuel burns out, even for a big charge.

 

 

 

 

I’ve read of cases where people have been using a bench grinder to grind aluminium/aluminium where the grinding swarf has mixed with steel/iron swarf that had rusted. (Ferrous Oxide)? This mixture / compound was then ignited by a spark when steel was subsequently ground, with apparently horrendous results. I seem to remember, I had also read that “Thermit” was used in some anti-ship ordnance instead of explosives, the reasoning being that the intense heat generated would melt through the deck plating and could cause more damage than an explosion for the size of “bomb” used!

[Horse Newbie 7,057]

10 hours ago, bcgold said:

Kids prbably got their hands on a couple of sacks of thermite, used by the railways for track welds.

 

Thermite burns at about 5000 degrees F., or half the temperature at the surface of the sun.

How deeply it will burn of course depends on the amount of fuel available. Most of the heat, of course, will go upward. Some ash will form, which will insulate the concrete to a degree, and further impede downward burning. So, as a guess, I would think it would only burrow down an inch or two before the fuel burns out, even for a big charge.

 

 

 

 

Good guess I guess, but that's not it.

[Horse Newbie 7,057]

10 hours ago, Jeff-C175 said:

Is there a back story?  Do you know the answer?

Yes, I know the answer... I had two guesses and one of them was correct.

I confirmed it through my boss at work.

[Horse Newbie 7,057]

5 hours ago, ebinmaine said:

I gotta go 🌩️🌩️⚡⚡⚡⚡ Lightning ⚡⚡⚡⚡⚡⚡

That was one of my guesses...here's 2 pics of lightning damage to a sidewalk...

[Mickwhitt 4,593]

Looks quite different to your damage.  More surface than burn through.

 

[Horse Newbie 7,057]

Okay fellows,

You guys came up with some very insightful and possible answers, but what it was is quite simple...a man was walking his Chihuahua down the street after eating at a Mexican restaurant, the dog farted, and this was the aftermath...

The dog and the man both survived...the man only receiving minor burns on his feet, and having to buy new shoes and socks...the dog was found 3 blocks away, unharmed, lodged between two branches in a tree, with singed butt hair...

Edited March 6, 2021 by Horse Newbie

[Handy Don 12,163]

High voltage buried line going bad released a lot of heat. Boiling moisture in soil creates steam which can cause an "explosion". Stories of manhole covers being thrown hundred of feet due to electrical shorts in flooded manholes are pretty commonly reported.

Edited March 6, 2021 by Handy Don

[Horse Newbie 7,057]

What actually happened was...

A car struck a utility pole, broke a/ some wires, and when the wires grounded to the earth it must have been fireball city !

I was not there when it happened and glad I wasn't. 

My 2 guesses were lightning or power lines...

 

Now I'm no electrical expert by no means, but it seems to me that if a single buried power line would be damaged or fail, it would just ground through the surrounding earth and possibly do no more than "throw" a breaker.

If two wires failed, or were damaged, and arced together I could see the welding effect, and heat being produced "shoot" up through the earth or sidewalk.

If you look close at the pics, you can see molten rock/ concrete...it must have been very hot.

From what I understand, this power line fell from a pole...

Edited March 7, 2021 by Horse Newbie

[Horse Newbie 7,057]

Thank you guys for jumping in...gave this semi-getting old man a good chuckle !

[Mickwhitt 4,593]

The chihuahua was funnier than the real thing.

 

Electricity is weird stuff, it does some pretty odd things that you wouldn't expect.

 

We had an electrician commit suicide over here by wiring himself into the mains. He fixed all the fuses so they could not blow and used heavy duty cable to connect himself up.

He also put warning signs all around himself so no one would get hurt when they found him. 

Poor guy, must have been in a state to come up with the idea and go through with it.

Glad to have cheered you all up.

[oldlineman 1,481]

I worked a storm break several years ago in Detroit and saw several distribution lines on the ground burning. They hand solid line connections and the resulting short circuit to ground was not good enough to trip protection further down the line. Line would just lay there and burn till we got it off the ground and back  in the air. Bob